fast lens: what makes a fast lens more expensive is it because there are more components in the lens to let in more light or what. :idea:...

roy4711 Loc: Spring Valley IL.

what makes a fast lens more expensive is it because there are more components in the lens to let in more light or what. :idea:

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

More elements/groups, larger aperture to allow more light to fall on the sensor. Possibly low dispersion, apochromatic elements (or more of them) to name a few reasons...

Cdouthitt Loc: Traverse City, MI

A way around this is to go old school with manual focus lenses. You can find some great fast glass for cheap if you're willing to focus manually.

I'm always on the lookout for f/2 (ish) or faster glass on my forums.

amehta Loc: Boston

roy4711 wrote:

what makes a fast lens more expensive is it because there are more components in the lens to let in more light or what. :idea:

The fast lenses are also generally built better, to finer tolerances with better materials, because they are designed to be abused in the field. Their overall image quality is better, especially wide open, because they are designed with the understanding that they will be used in low light and fast moving conditions. And they usually are better at covering the entire frame with good image quality, while the slower "consumer" lenses often lose IQ at the edges. Of course, some is also paying for the prestige.

jerryc41 Loc: Catskill Mts of NY

roy4711 wrote:

what makes a fast lens more expensive is it because there are more components in the lens to let in more light or what. :idea:

Here's my thinking. With a larger maximum aperture, the glass is bigger, and glass like that is expensive. To maintain image quality at a larger aperture, the glass has to be really good, and manufacturing design and tolerances have to be equally good. Any defect will be magnified, so everything has to be that much better than in a lens with a smaller aperture.

bunuweld Loc: Arizona

jerryc41 wrote:

Here's my thinking. With a larger maximum aperture, the glass is bigger, and glass like that is expensive. To maintain image quality at a larger aperture, the glass has to be really good, and manufacturing design and tolerances have to be equally good. Any defect will be magnified, so everything has to be that much better than in a lens with a smaller aperture.

That makes very good sense. Never thought of it.

roy4711 Loc: Spring Valley IL.

Jerry that was a very good answer. :roll:

SharpShooter Loc: NorCal

roy4711 wrote:

what makes a fast lens more expensive is it because there are more components in the lens to let in more light or what. :idea:

Roy, there must be more there than meets the eye.
The Canon 200mm 2.8 lens costs $800 and weighs 1.7lbs. and is painted black.
The Canon 200mm 1.8 weighs five lbs more, and the current version costs $5000 more and is painted white. The paint can't possibly cost that much!! :lol:
SS

Nikonian72 Loc: Chico CA

jerryc41 wrote:

With a larger maximum aperture, the glass is bigger, and glass like that is expensive.

'Xactly!

lighthouse Loc: No Fixed Abode

roy4711 wrote:

what makes a fast lens more expensive is it because there are more components in the lens to let in more light or what. :idea:

Bigger glass, better light gathering, more expensive construction.
Some lenses contain flourite lenses.
These have to be grown in crystal form which brings a time factor into play and the costs associated with that.

From wikipaedia
Optics
Fluorite has a very low dispersion, so lenses made from it exhibit less chromatic aberration than those made of ordinary glass. However, naturally-occurring fluorite crystals without optical defects were only large enough to produce microscope elements.

With the advent of synthetically-grown fluorite (calcium fluoride crystal), it could be used instead of glass in some high-performance telescopes and camera lens elements. Its use for prisms and lenses was studied and promoted by Victor Schumann near the end of the 19th century.

In telescopes, fluorite elements allow high-resolution images of astronomical objects at high magnifications. Canon Inc. produces synthetic fluorite crystals that are used in their more expensive telephoto lenses.

Mercer Loc: Houston, TX, USA

JerryC41, it is UHH'ers like you and a few others who make this site such a good one. Your answer re lens quality/speed is a case in point. Thanks. :thumbup:

speters Loc: Grangeville/Idaho

SharpShooter wrote:

Roy, there must be more there than meets the eye.
The Canon 200mm 2.8 lens costs $800 and weighs 1.7lbs. and is painted black.
The Canon 200mm 1.8 weighs five lbs more, and the current version costs $5000 more and is painted white. The paint can't possibly cost that much!! :lol:
SS

There is no current version of the 200/1.8, it was discontinued a long time ago. The current version is the 200/f2 and yes, at $ 6000.00 it is not cheap.

LFingar Loc: Claverack, NY

jerryc41 wrote:

Here's my thinking. With a larger maximum aperture, the glass is bigger, and glass like that is expensive. To maintain image quality at a larger aperture, the glass has to be really good, and manufacturing design and tolerances have to be equally good. Any defect will be magnified, so everything has to be that much better than in a lens with a smaller aperture.

Very thorough answer. I may have to bookmark this page!
:thumbup:
Sorry Jerry, couldn't help myself!

SharpShooter Loc: NorCal

speters wrote:

There is no current version of the 200/1.8, it was discontinued a long time ago. The current version is the 200/f2 and yes, at $ 6000.00 it is not cheap.

I tell ya, must be the paint!! :lol:
SS

Virgil Loc: The Hoosier State

[Besides what Jerry has said, I think the 'body' of the lens has to be beefed up some to handle the wear and tear of the extra weight of the glass elements and to have more precision when moving the elements.